Question

Find the mode of the following data:

Class:	1-3	3-5	5-7	7-9	9-11
Frequency:	7	8	2	2	1

Answer 1

1. The modal class is 3 – 5, with the greatest frequency, 8. 

Thus, l = 3, h = 2, f = 8, f₁ = 7 and f₂ = 2.

2. Apply the grouped-data mode formula:

\[\text{Mode}=3+\frac{8-7}{2(8)-7-2}\times2=3+\frac{2}{7}\approx3.29\]

3. Therefore, the mode is approximately 3.29.